by James Clark and Benjamin Funk
The defensive shift in baseball is typically viewed as a new-age strategy, but it dates back all the way to the 1940s. The most notable early use of this tactic was against one of baseball’s greatest hitters, Ted Williams. Ted Williams is in the top 10 for career batting averages and had one of the best hitting seasons in MLB history when he topped a .400 batting average in 1941. Teams quickly became desperate, trying anything they could to stop him. Finally, a successful strategy was developed by Cleveland Indians player-manager Lou Boudrea known as “The Ted Williams Shift” in 1946. (Zeegers, 2019). In the middle of a double header between Cleveland and Boston, Boudrea changed his strategy by implementing an infield shift that would move an extra infielder to the pull side of Williams. This strategy of an infield shift became so successful that it started to be used by other teams. Some managers went as far as to move all but one defender to the right side of the diamond in the future. Even Williams himself admitted that it
may have possibly shaved 15 points off his career batting average (Zeegers, 2019). However, as time went on, Williams adapted to the shift. Williams’ approach at the plate from that point on was simple, if he got pitched away he would hit the ball to the gap and if he got pitched inside he would hit the ball over the shift.
The defensive shift was rarely deployed except for the occasional superstar until the 2010s when the shift started to become a regular occurrence. The modern-day defensive shift was popularized by the Rays manager Joe Maddon (Atkins, 2012). Other teams followed suit and now the defensive shift is a regular occurrence in baseball. During the 2015-2021 seasons an infield shift was used about 1 in 5 batters. This movement has been accompanied by a lack of offensive production over the last decade which is leading some to call for a ban of the defensive shift. Commissioner of the MLB, Rob Manfred, himself has proposed banning the defensive shift (Yellon, 2021).
In this study, we analyze how infield shifts affect a batters’ performance. Using data from the 2015 – 2021 seasons, we estimate statistical models to show how the defensive shifts affect wOBA (weighted on base average) and BABIP (batting average on balls in play). We analyze how the use of the defensive shift changes within a game (early inning vs later innings, games within one run, regular vs postseason games, etc.) and how effective the shift is in reducing batters’ performance.
Our analysis suggests that when a team implements a defensive shift, the batter is less likely to get a base hit, but their overall offensive contribution increases slightly. We also find that batters hit home runs and walk at a higher rate when facing an infield shift compared to standard defenses. We do not find that any defense becomes more or less effective in later innings compared to earlier innings. Likewise, we do not find evidence that shifts become less effective in the postseason.
This paper has been accepted to the Baseball Hall of Fame Cooperstown Symposium Conference, June 2020
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